If you're on a strict VLCD and feel you need a break, then following a more controlled 'day off' is probably the best thing (so protein and salad). As you are at the bottom of your glycogen stores, all you do is end up refilling them (hence sometimes a significant gain) which takes time to deplete again to go back into the fat burning zone. Having carbs on a VLCD will make you feel sluggish and groggy the next day as the body gets used to the packs and the depleted state. The hunger will return and it's harder to motivate yourself to get back on the packs.
While I do believe a day off can sometimes kick-start the process (if there's a plateau), 2 days a week seems a bit too much. While you WILL lose weight (depending on the excess of course), it will come off but a lot more slowly... So you have to think long-term, whether you'd like the diet to keep going for significantly longer or whether you'd like to have longer periods of 100% and be done quicker? It all comes down to your own personal needs and mindset.
When I was dieting previously (not a VLCD - but a fasting + small calorie controlled dinner) a day off per week was fine, but I also had an active job where I was on my feet all day, so I still lost weight. But with two off days the weight loss did stall.